Multi-pole reed switch relay



Dec. 19, 1967 J. P. JONES, JR

MULTI-POLE REED SWITCH RELAY Filed Sept. 24. 1964 COM.

' INVENTOR 1 VOLTAGE JOHN PAUL JONES, JR.

ATTORNEYS United States Patent 3,359,463 MULTl-POLE REED SWlTCH RELAY John Paul Jones, in, Wynnewood, Pa., assignor to Navigation Computer Corporation, Norristown, Pa., a corporation of Pennsylvania Filed Sept. 24, 1964, Ser. No. 399,025 8 Claims. (Cl. 317-123) ABSTRACT OF THE DISCLQSURE Magnetic reed switches are mounted to span the poles of an electromagnetic core comprising a U-shaped channel. To produce uniform operation of all switches, a non-magnetic gap is introduced to hold the switch reeds a known distance from the poles of the core. Printed circuit structure and mounting details permit inspection and separate removal of any one reed switch without disturbing others. A particular configuration is provided with .two separate channels operating two sets of reeds in class C fashion.

This application relates in general to multiple pole relays and in particular relates to multiple pole relays having large numbers of contacts for operation in a variety of different isolated circuits.

In producing relay circuits for operations in systems for electronic control or digital analysis many occasions arise where it is desirable to use large numbers of relay contacts, say in the order of fifteen to twenty contacts. A problem arises in the use of such relays particularly in ,systems which require fast response, in that the more contacts supplied, the more power is required to operate a relay. This leads to the provision of very large coils inherently containing a considerable amount of mechanical and electromechanical delay, so that operation is far from instantaneous. Furthermore the amount of power expended in such relays keeps them from being efficient.

Another shortcoming of conventional contact relays is that it is difficult, if not impossible, to inspect the contacts during normal maintenance procedures or during operation to determine whether faulty operation is taking place. Thus, it is extremely desirable to provide improved relays with multiple contacts which may be visually inspected at all times.

Another problem with large multi-pole relays is that the contact assemblies are generally integral with the entire relay assembly so that failure of one set of contacts means in essence failure of an entire expensive relay unit. There is rarely provision in the state of the prior art in relay devices which provides for the convenient interchanging of a single contact set in the event of its failure. Even if such a contact were replaceable it is entirely impractical in the field to do such in most instances because of the many wires which may be soldered directly to terminals of the contacts and which must be removed and replaced to obtain access to the particular contact set which is being repaired.

Accordingly it is a primary object of the present invention to improve the state of the art in providing convenient multi-pole relays in which the separate sets of contacts may be visually inspected and easily replaced.

To accomplish this objective therefore the present invention utilizes a novel structural arrangement providing a plurality of sealed in glass type magnetic switches aligned along the edges of a U-shaped ferromagnetic channel on which is wound an electromagnetic actuating coil. In this manner the number of switches used with the U-shaped ferromagnetic core member is optional and requires only that number selected for the particular circuits involved in any desirable application. Since only the number of contacts actually used need be mounted, the relay comprises a semi-custom device thereby making the relay configuration universally applicable and inexpensive to use. The sealed in glass type switches may be visually inspected as they are laid side by side along the U-shaped channel, and repair of the assembly by removing any particular contact is simply achieved in the field without disturbing additional wires or wiring. In order to insure visibility of inspection of the contacts in such a relay, a transparent dust-proof cover is provided.

Although the sealed in glass type magnetic switches discussed are very fast in operation and quite reliable in electronic circuits it has been difficult in the prior art to operate such switches to perform the C-type single-pole, double-throw configuration.

Thus, it is another object of the invention to provide single-pole, double-throw configurations utilizing sealed in glass type magnetic switches.

Another object of the invention is to provide a multiple pole relay in which the desired member of contacts may be mounted to comply with the requirement of any specialized system.

A still further object of the invention is to provide a multiple pole relay configuration which can very simply be repaired without disturbing the overall relay operation or wiring while replacing a single contact set.

Yet another object of the invention is to provide a multiple contact relay wherein each of the switching contacts is always available for visual inspection to determine whether operation is normal.

Still another object of the invention is to provide a multiple pole relay which is efficient in operation and can be driven at very high speeds with little power such as that supplied directly from transistor switching circuitry.

In achieving the class C type of operation with singlepole, double-throw contacts, the above-described multiple pole relay, utilizing a series of sealed in glass magnetic reed switches mounted upon a U-shaped ferromagnetic core member, is fashioned to use two class A single-pole, single-throw glass reed type switches in a pair to give the class C operation. Thus, in essence two side by side U-shaped channels may be used in which the winding upon the ferromagnetic core is fashioned to provide an electromagnetic bias for holding contacts on one set of the switches closed. The other set of switches is normally open and the C-type switch includes one switch from each set. There is then provision for a further circuit winding associated with the biased contact which overcomes the bias to open the magnetic contact upon receipt of a signal pulse, whereas the open contact is provided with an operating coil simultaneously operated to close the contact upon receipt of the signal pulse.

In order to provide simple repairability and easy access to each contact without disturbing wiring, the entire relay assembly is mounted upon a printed circuit board which has mounting posts extending from the insulated board on each side of the U-shaped channel so that each magnetic switch assembly may be laid alongside the extending posts and soldered thereto.

Since the number of switches along the channel are to be varied between a small number and possibly an extremely large number such as 20 or 30, the circuit must be designed so that there is no interaction in operation of the circuit dependent upon the number of switches incorporated in the relay. Accordingly, each relay which is sealed in glass with two extending magnetic reeds is a magnetic bridge for the U-shapecl channel. It has been found that if the extending reeds are not positioned in direct ferromagnetic contact with the U-shaped channel but have interspersed therebetween a non-magnetic gap which may be in the form of a thin layer of insulating material; this provides a magnetic leakage path between the magnetic reeds and the ferromagnetic core so that the magnetic gap is not shunted by the reed of the remaining glass switches. Thus, the problem of loading upon the relay or shunting of the magnetic field by an addition of more magnetic reed switches is avoided; and all circuits behave similarly no matter what number is employed.

This relay configuration has other features and objectives which will be described throughout the following specification which is referenced to the accompanying drawing, wherein:

FIGURE 1 shows a perspective view of a relay unit constructed in accordance with the invention with portions thereof cut away;

FIGURE 2 shows an end view in cross section of the core assembly as afforded by the invention;

FIGURE 3 is a circuit diagram of a relay configuration afforded by the invention to operate as a single-pole, double-throw relay circuit.

The basic parts of the relay shown in FIGURE 1 comprise a mounting panel 5 which is essentially an insulated board comprising an etched circuit base panel. Mounted upon this base panel are core mounting blocks 6 which hold a pair of U-shaped elongated ferromagnetic cores 7 and 8. Each core has a coil 9 Wound longitudinally in the channel to provide an electromagnetic field for operation of the sealed in glass magnetic reed switches 10 arrayed along the top of the U-shaped channel. As may be seen from FIGURE 2, the reed switches have the extending magnetic reeds 11 and 12 positioned from the channel 8 by a spacer 14 which provides a non-magnetic gap to prevent the shunting out of the core section by any one relay switch, to thereby provide for substantially identical operation of the relay without regard to the number of reed switches mounted thereon. The channel section of the core provides a convenient form member for the winding of the coil 9 as may be seen by the end section view of FIGURE 2.

Each sealed inglass magnetic reed relay switch is laid on top of the channel 7 or 8 and is mounted by soldering to a pair of posts 18 which are affixed to the insulating panel 5 and extend on either side of the U-shaped channel 8. Thus as may be seen from the view of FIGURE 1 it is quite convenient to vary the number of switches in each relay channel section by providing only those switches at the extending posts that are necessary for any particular circuit in operation. They may be packed densely near each other as in channel 7 or spaced in distributed manner as shown on channel 8, to afford room for as many as required in side by side position along the channels. It is also seen that in the event of contact failure the sealed in glass reeds permit through the transparent cover member 20 a visual observation so that should they show abnormality in operation or in static position. Should the contacts become eroded or welded together or otherwise fail to operate, the relay may be replaced simply by unsoldering a single glass switch and replacing it with another.

It is significant in this configuration that each of the terminal posts 18 is connected to a printed circuit wire 21 on either side of the board, which extends to one of the terminal portions of the board 22 at either end, upon which maybe mounted a connector 23 as shown at one end thereof. This provides an ordered set of wiring for the relay so that the contacts may be removed without requiring access to circuit wiring which is made to the circuit plug 23 rather than to the relay directly or the contacts thereof. Accordingly it is evident that the lay out of the present relay provides improved repairability over conventional relay configurations.

Because of the flat plane open style construction of the core member 8 shown in the drawing which is designated by the descriptive term U-shaped channel, the coil wound thereupon may have many turn-s. This together with the very small air gaps in the reed contact switch serving to complete the magnetic circuit of the cores comprising the U-shaped channels, permits very efficient operation at low power levels such as may be supplied from switching transistor circuits. Typical ratings of a multiple pole relay such as shown with in the order of 24 sets of contacts are about 50 milliamperes at 12 to 18 volts, which represents ordinary logic switching levels in usual computer type systems. This may be contrasted with the extremely high power levels required to operate a conventionally formed relay having 24 sets of spring leaf contacts for simultaneous operation. It is also evident that because of the use of the magnetic reed switches in this configuration that the switching times are very fast as compared with the large build up of electromagnetic and mechanical inertia required to operate a conventional relay having a large number of spring leaf contacts. Each switch is closed without dependence upon loading of any other switch. Thus, it is seen that this configuration of a multipole switch relay is advantageous over prior art devices.

With reference to FIGURE 3 a pair of reed switches 30 and 31 is connected with terminals 32, 33 and 34 to provide class C-type operation of single-pole, double-throw nature. Thus, reed switch 30 has open contacts; and reed switch 31 has closedcontacts. Consider coil 35 to be wound in channel 7 of the open contact relay 30 and the two coil sections 36 and 39 to be wound in the channel 8 of the closed circuit relay 31. It is to be noted that a negative voltage supply is connected to terminal 37 which provides a bias current flow through winding 36 to grounded point 38 which keeps the reeds of switch 31 normally closed. Diodes 40, 41 provided in the circuit between the negative voltage supply at point 37 and the terminal point 42 prevents sneak current flow through the winding 36 by way of windings 35 and 39 so that these windings normally have no current flow therein until the actuation switch or signal input circuit corresponding thereto designated by reference character 43 is operated to put point 42 at ground potential. When this happens the current flow through winding 39 is in phase opposition to that flowing in winding 36, as shown by the dots at each end of the respective windings referenced to the negative voltage potential input 37 to the windings. Thus when switch 43 is closed winding 39 will cancel out and overcome the bias provided by winding 36 and permit the normally closed contact 31 to open. Simultaneously current flowing through winding 35 will cause the switch 30 to close its contacts and thereby provide the transfer operation required of class C-type contacts at terminals 32, 33 and 34.

It is therefore seen that this configuration as associated with the relay constructed as shown in FIGURE 1 provides a maximum flexibility of operation between normally-open, normally-closed, or transfer-type contacts which may be operated in any circuit configuration desired by connections to the printed circuit plug 23.

It is evident therefore that in accordance with the present invention that a novel and improved relay configuration is provided and those features of novelty believed descriptive of the nature of the invention are defined with particularity in the following claims.

What is claimed is:

1. A multiple pole reed switch relay comprising a U- shaped channel core of ferromagnetic material, a coil wrapped along the channel of said core, and means holding a plurality of sealed magnetic reed switches across said channel having magnetic reeds adjacent both ends of the U of said channel, and a non-magnetic gap member placed between at least one of said magnetic reeds and the ferromagnetic material to create a nonmagnetic space between said core and said reeds.

2. A relay as defined in claim 1, wherein the relay is provided with a mounting comprising an insulated printed circuit board, wherein the means for holding the reed switches are conductive posts mounted in said board alongside said U-shaped channel, and printed wiring on said board connects said posts to edge portions adapted to receive a plug connector.

3. A multi-pole reed switch relay comprising in combination, an elongated U-shaped channel of ferromagnetic material, a coil wound longitudinally in said channel, a plurality of hermetically sealed magnetic reed switches each having a magnetic reed portion extending therefrom at two ends to fit upon the open ends of said U-shaped channel to form therewith a substantially completely closed magnetic path, a non-magnetic gap forming spacer on the channel between the ferromagnetic material and at least one of said extending magnetic reed portions, in said magnetic path, and mounting means comprising an insulating board with conductive posts mounted thereon along each side of said channel to receive said reed portions in conductive contacts.

4. A relay as defined in claim 3 wherein two similar channels are mounted side by side and one coil has two sections, each channel having said posts to receive a plurality of said reed switches, circuit means coupled to one of said two coil sections to hold switches mounted on the corresponding said channel closed and coupled to the other coil to hold those switches on the other said channel open, and means for providing a selective signal to said circuit means to change the condition of switches on both channels simultaneously.

5. A relay as defined in claim 4 wherein the circuit for said coil having two sections comprises means coupling a steady bias current through one section to hold the reed contacts closed, and a circuit coupling a signal current through the other section in phase opposition to the bias to cancel its magnetic field and cause said reed contacts to open.

6. A relay as defined in claim 3, wherein a transparent dust cover is mounted on said insulating board to enclose the channel and permit visual inspection of said reed switches.

7. A multiple pole reed switch relay comprising a plurality of reed switches each comprising two magnetic reeds sealed to extend from a switch housing, an electromagnetic coil wound for selectively creating opposite magnetic poles, a common ferromagnetic core for presenting said two opposite magnetic poles to meet each of said two magnetic reeds of each switch forming a substantially closed magnetic path, and a non-magnetic gap spacing member placed in said magnetic path to create a non-magnetic space of such length that all said reeds are operated by a magnetic field induced by said coil but preventing substantial short circuiting of the magnetic path between said poles by the two magnetic reeds.

8. A relay as defined in claim 7 wherein the core comprises a U-shaped channel member.

References Cited UNITED STATES PATENTS 3,188,424 6/1965 Else et al. 335-152 MILTON O. HIRSHFIELD, Primary Examiner. L. T. HIX, Examiner. 

1. A MULTIPLE POLE REED SWITCH RELAY COMPRISING A USHAPED CHANNEL CORE OF FERROMAGNETIC MATERIAL, A COIL WRAPPED ALONG THE CHANNEL OF SAID CORE, AND MEANS HOLDING A PLURALITY OF SEALED MAGNETIC REEDS ADJACENT BOTH ENDS SAID CHANNEL HAVING MAGNETIC REEDS ADJACENT BOTH ENDS OF THE U OF SAID CHANNEL, AND A NON-MAGNETIC GAP MEMBER PLACED BETWEEN AT LEAST ONE OF SAID MAGNETIC REEDS AND THE FERROMAGNETIC MATERIAL TO CREATE A NON-MAGNETIC SPACE BETWEEN SAID CORE AND SAID REEDS. 